Persistence of Escherichia coli O157:H7 on Lettuce Plants following Spray Irrigation with Contaminated Water

2003 ◽  
Vol 66 (12) ◽  
pp. 2198-2202 ◽  
Author(s):  
ETHAN B. SOLOMON ◽  
HOAN-JEN PANG ◽  
KARL R. MATTHEWS
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Sampling Period ◽  
Repeated Exposure ◽  
Human Consumption ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
Plant Leaves ◽  
E Coli ◽  
Spray Irrigation

Irrigation water collected at farms growing crops for human consumption was artificially contaminated with E. coli O157: H7 and used to irrigate lettuce plants. Plants in a growth chamber were spray irrigated either once or intermittently with water contaminated with 102 or 104 CFU of E. coli O157:H7 per ml and were then sampled over a 30-day period. Only plants exposed to 102 CFU/ml on day 1 did not harbor the pathogen at the end of the sampling period. All other treatments resulted in contaminated plants at harvest. Plants irrigated with 104 CFU/ml contained high levels (up to 5 log CFU/g) of the pathogen at harvest. The results obtained in this study underscore the assertion that spray irrigation (the application of water directly to plant leaves) is linked to the contamination of crops and suggest that repeated exposure increases the E. coli O157:H7 level on the plant.

Internalization of Escherichia coli O157:H7 following Spraying of Cut Shoots When Leafy Greens Are Regrown for a Second Crop

2013 ◽  
Vol 76 (12) ◽  
pp. 2052-2056 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
JUAN CARLOS DÍAZ-PÉREZ ◽  
LINDSEY E. DAVEY ◽  
ALISON S. PAYTON ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Tissue Repair ◽  
Contamination Level ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Spraying Plants ◽  
High Level

Both spinach and lettuce were grown to harvest, cut, and then regrown after spraying the cut shoots with irrigation water contaminated with Escherichia coli O157:H7. Plant tissue was collected on the day of spraying and again 2 and 14 days later for analysis of total and internalized E. coli O157:H7 populations. Internalization of E. coli O157:H7 occurred on the day of spraying, and larger populations were internalized as the level in the spray increased. Tissue repair was slow and insufficient to prevent infiltration of E. coli O157:H7; internalized E. coli O157:H7 in shoots cut 5 days prior to exposure to E. coli O157:H7–contaminated water were not significantly different from levels in shoots cut on the same day of spraying with contaminated water (P > 0.05). Two days after spraying plants with a high level of E. coli O157:H7 (7.3 log CFU/ml), levels of internalized E. coli O157:H7 decreased by ca. 2.6 and 1.3 log CFU/g in Tyee and Bordeaux spinach, respectively, whereas populations of internalized E. coli O157:H7 decreased very little (ca. 0.4 log CFU/g) in lettuce plants that had been sprayed either on the same day as cutting or 1 day after cutting. When cut plants were sprayed with irrigation water at a lower contamination level (4.5 log CFU/ml), internalized E. coli O157:H7 was not detected in either spinach or lettuce plants 2 days later and therefore would not likely be of concern when the crop was harvested.

Effect of Irrigation Method on Transmission to and Persistence of Escherichia coli O157:H7 on Lettuce

2002 ◽  
Vol 65 (4) ◽  
pp. 673-676 ◽  
Author(s):  
ETHAN B. SOLOMON ◽  
CATHERINE J. POTENSKI ◽  
KARL R. MATTHEWS
Keyword(s):  
Escherichia Coli ◽  
Water Immersion ◽  
Contaminated Water ◽  
Microbial Quality ◽  
Escherichia Coli O157 ◽  
Surface Irrigation ◽  
Single Exposure ◽  
E Coli ◽  
Irrigation Method ◽  
Spray Irrigation

In this study, the transmission of Escherichia coli O157:H7 to lettuce plants through spray and surface irrigation was demonstrated. For all treatments combined, the number of plants testing positive following a single exposure to E. coli O157: H7 through spray irrigation (29 of 32 plants) was larger than the number testing positive following surface irrigation (6 of 32 plants). E. coli O157:H7 persisted on 9 of 11 plants for 20 days following spray irrigation with contaminated water. Immersion of harvested lettuce heads for 1 min in a 200 ppm chlorine solution did not eliminate all E. coli O157:H7 cells. The results of this study suggest that regardless of the irrigation method used, crops can become contaminated; therefore, the irrigation of food crops with water of unknown microbial quality should be avoided.

Surface and Internalized Escherichia coli O157:H7 on Field-Grown Spinach and Lettuce Treated with Spray-Contaminated Irrigation Water

2010 ◽  
Vol 73 (6) ◽  
pp. 1023-1029 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
JUAN CARLOS DIAZ-PEREZ ◽  
SHARAD C. PHATAK ◽  
JOHN J. SILVOY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Enrichment Culture ◽  
Field Studies ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Contaminated Irrigation Water

Numerous field studies have revealed that irrigation water can contaminate the surface of plants; however, the occurrence of pathogen internalization is unclear. This study was conducted to determine the sites of Escherichia coli O157:H7 contamination and its survival when the bacteria were applied through spray irrigation water to either field-grown spinach or lettuce. To differentiate internalized and surface populations, leaves were treated with a surface disinfectant wash before the tissue was ground for analysis of E. coli O157:H7 by direct plate count or enrichment culture. Irrigation water containing E. coli O157:H7 at 102, 104, or 106 CFU/ml was applied to spinach 48 and 69 days after transplantation of seedlings into fields. E. coli O157:H7 was initially detected after application on the surface of plants dosed at 104 CFU/ml (4 of 20 samples) and both on the surface (17 of 20 samples) and internally (5 of 20 samples) of plants dosed at 106 CFU/ml. Seven days postspraying, all spinach leaves tested negative for surface or internal contamination. In a subsequent study, irrigation water containing E. coli O157:H7 at 108 CFU/ml was sprayed onto either the abaxial (lower) or adaxial (upper) side of leaves of field-grown lettuce under sunny or shaded conditions. E. coli O157:H7 was detectable on the leaf surface 27 days postspraying, but survival was higher on leaves sprayed on the abaxial side than on leaves sprayed on the adaxial side. Internalization of E. coli O157:H7 into lettuce leaves also occurred with greater persistence in leaves sprayed on the abaxial side (up to 14 days) than in leaves sprayed on the adaxial side (2 days).

A Comparison of the Survival in Feces and Water of Escherichia coli O157:H7 Grown under Laboratory Conditions or Obtained from Cattle Feces

2006 ◽  
Vol 69 (1) ◽  
pp. 6-11 ◽  
Author(s):  
L. SCOTT ◽  
P. McGEE ◽  
J. J. SHERIDAN ◽  
B. EARLEY ◽  
N. LEONARD
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogen ◽  
Hemorrhagic Colitis ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Cattle Feces ◽  
Oral Inoculation ◽  
Before And After ◽  
Uremic Syndrome

Escherichia coli O157:H7 is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic uremic syndrome. Cattle feces and fecally contaminated water are important in the transmission of this organism on the farm. In this study, the survival of E. coli O157:H7 in feces and water was compared following passage through the animal digestive tract or preparation in the laboratory. Feces were collected from steers before and after oral inoculation with a marked strain of E. coli O157:H7. Fecal samples collected before cattle inoculation were subsequently inoculated with the marked strain of E. coli O157:H7 prepared in the laboratory. Subsamples were taken from both animal and laboratory-inoculated feces to inoculate 5-liter volumes of water. E. coli O157:H7 in feces survived up to 97 days, and survival was not affected by the method used to prepare the inoculating strain. E. coli O157:H7 survived up to 109 days in water, and the bacteria collected from inoculated cattle were detected up to 10 weeks longer than the laboratory-prepared culture. This study suggests that pathogen survival in low-nutrient conditions may be enhanced by passage through the gastrointestinal tract.

Infrequent Internalization of Escherichia coli O157:H7 into Field-Grown Leafy Greens

2010 ◽  
Vol 73 (3) ◽  
pp. 500-506 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
JUAN CARLOS DIAZ-PEREZ ◽  
SHARAD C. PHATAK ◽  
JOHN J. SILVOY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Field Studies ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Contaminated Irrigation Water ◽  
Green Fluorescent ◽  
Field Plots ◽  
Spinach Leaves

Several sources of contamination of fresh produce by Escherichia coli O157:H7 (O157) have been identified and include contaminated irrigation water and improperly composted animal waste; however, field studies evaluating the potential for internalization of O157 into leafy greens from these sources have not been conducted. Irrigation water inoculated with green fluorescent plasmid–labeled Shiga toxin–negative strains (50 ml of 102, 104, or 106 CFU of O157 per ml) was applied to soil at the base of spinach plants of different maturities in one field trial. In a second trial, contaminated compost (1.8 kg of 103 or 105 CFU of O157 per g) was applied to field plots (0.25 by 3.0 m) prior to transplantation of spinach, lettuce, or parsley plants. E. coli O157:H7 persisted in the soil up to harvest (day 76 posttransplantation) following application of contaminated irrigation water; however, internalized O157 was not detected in any spinach leaves or in roots exposed to O157 during the early or late growing season. Internalized O157 was detected in root samples collected 7 days after plants were contaminated in mid-season, with 5 of 30 samples testing positive for O157 by enrichment; however, O157 was not detected by enrichment in surface-disinfected roots on days 14 or 22. Roots and leaves from transplanted spinach, lettuce, and parsley did not internalize O157 for up to 50 days in the second trial. These results indicate that internalization of O157 via plant roots in the field is rare and when it does occur, O157 does not persist 7 days later.

Transfer of Escherichia coli O157:H7 to Romaine Lettuce due to Contact Water from Melting Ice

2008 ◽  
Vol 71 (2) ◽  
pp. 252-256 ◽  
Author(s):  
JIN KYUNG KIM ◽  
MARK A. HARRISON
Keyword(s):  
Escherichia Coli ◽  
Tap Water ◽  
Sampling Site ◽  
Contaminated Water ◽  
Escherichia Coli O157 ◽  
Romaine Lettuce ◽  
E Coli ◽  
Ice Melt ◽  
Leaf Surfaces ◽  
Shipping Containers

Ice can be used to chill romaine lettuce and maintain relative humidity during transportation. Escherichia coli O157:H7 may contaminate water used for ice. The objective of this study was to determine the potential for E. coli O157:H7 contamination of romaine lettuce from either ice contaminated with the pathogen or by transfer from lettuce surfaces via melting ice. In experiment 1, lettuce was spot inoculated with E. coli O157:H7 and chilled with ice prepared from uncontaminated tap water. In experiment 2, water inoculated with this pathogen was frozen and used to ice lettuce. Three heads of lettuce were stacked in each container and stored at 4 or 20°C. After the ice melted, E. coli O157:H7 attachment to and recovery from the lettuce leaves were determined. For experiment 1, the population of E. coli O157:H7 attached to inoculated sites averaged 3.8 and 5.5 CFU/cm2 at 4 and 20°C, respectively. Most of the uninoculated sites became contaminated with the pathogen due to ice melt. For experiment 2, 3.5 to 3.8 log CFU E. coli O157:H7 per cm2 was attached to the top leaf on the first head. After rinsing with chlorinated water (200 μg/ml), E. coli O157:H7 remained on the surface of the top head (1.8 to 2.0 log CFU/cm2). There was no difference in numbers of E. coli O157:H7 recovered from each sampling site at 4 and 20°C. Results show that E. coli O157:H7 can be transferred onto other produce layers in shipping containers from melted ice made of contaminated water and from contaminated to uncontaminated leaf surfaces.

Persistence of Enterohemorrhagic Escherichia coli O157:H7 in Soil and on Leaf Lettuce and Parsley Grown in Fields Treated with Contaminated Manure Composts or Irrigation Water

2004 ◽  
Vol 67 (7) ◽  
pp. 1365-1370 ◽  
Author(s):  
MAHBUB ISLAM ◽  
MICHAEL P. DOYLE ◽  
SHARAD C. PHATAK ◽  
PATRICIA MILLNER ◽  
XIUPING JIANG
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Poultry Manure ◽  
Dairy Manure ◽  
Enterohemorrhagic Escherichia Coli ◽  
Avirulent Strain ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Manure Compost ◽  
Contaminated Irrigation Water

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 infections associated with lettuce and other leaf crops have occurred with increasing frequency in recent years. Contaminated manure and polluted irrigation water are probable vehicles for the pathogen in many outbreaks. In this study, the occurrence and persistence of E. coli O157:H7 in soil fertilized with contaminated poultry or bovine manure composts or treated with contaminated irrigation water and on lettuce and parsley grown on these soils under natural environmental conditions was determined. Twenty-five plots, each 1.8 by 4.6 m, were used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but treated with contaminated water) and five replication plots for each treatment. Three different types of compost, PM-5 (poultry manure compost), 338 (dairy manure compost), and NVIRO-4 (alkaline-stabilized dairy manure compost), and irrigation water were inoculated with an avirulent strain of E. coli O157:H7. Pathogen concentrations were 107 CFU/g of compost and 105 CFU/ml of water. Contaminated compost was applied to soil in the field as a strip at 4.5 metric tons per hectare on the day before lettuce and parsley seedlings were transplanted in late October 2002. Contaminated irrigation water was applied only once on the plants as a treatment in five plots for each crop at the rate of 2 liters per plot 3 weeks after the seedlings were transplanted. E. coli O157:H7 persisted for 154 to 217 days in soils amended with contaminated composts and was detected on lettuce and parsley for up to 77 and 177 days, respectively, after seedlings were planted. Very little difference was observed in E. coli O157:H7 persistence based on compost type alone. E. coli O157:H7 persisted longer (by >60 days) in soil covered with parsley plants than in soil from lettuce plots, which were bare after lettuce was harvested. In all cases, E. coli O157:H7 in soil, regardless of source or crop type, persisted for >5 months after application of contaminated compost or irrigation water.

Transmission of Escherichia coli O157:H7 to Internal Tissues and Its Survival on Flowering Heads of Wheat

2015 ◽  
Vol 78 (3) ◽  
pp. 518-524 ◽  
Author(s):  
BISMARCK MARTINEZ ◽  
JAYNE STRATTON ◽  
ANDRÉIA BIANCHINI ◽  
STEPHEN WEGULO ◽  
GLEN WEAVER
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Escherichia Coli O157 ◽  
Human Pathogen ◽  
Contamination Source ◽  
Wheat Seedlings ◽  
E Coli ◽  
Uremic Syndrome ◽  
Low Levels ◽  
Fourth Experiment

Escherichia coli O157:H7 is a human pathogen that can cause bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. E. coli O157:H7 illnesses are mainly associated with undercooked beef; however, in recent years, outbreaks have been linked to fresh produce, such as spinach, lettuce, and sprouts. In 2009, flour was implicated as the contamination source in an outbreak involving consumption of raw cookie dough that resulted in 77 illnesses. The objectives of this research were to determine (i) whether E. coli O157:H7 could be translocated into the internal tissues of wheat (Triticum aestivum) seedlings from contaminated seed, soil, or irrigation water and (ii) whether the bacterium could survive on flowering wheat heads. The levels of contamination of kanamycin-resistant E. coli O157:H7 strains in seed, soil, and irrigation water were 6.88 log CFU/g, 6.60 log CFU/g, and 6.76 log CFU/ml, respectively. One hundred plants per treatment were sown in pot trays with 50 g of autoclaved soil or purposely contaminated soil, watered every day with 5 ml of water, and harvested 9 days postinoculation. In a fourth experiment, flowering wheat heads were spray inoculated with water containing 4.19 log CFU/ml E. coli O157:H7 and analyzed for survival after 15 days, near the harvest period. To detect low levels of internalization, enrichment procedures were performed and Biotecon real-time PCR detection assays were used to determine the presence of E. coli O157:H7 in the wheat, using a Roche Applied Science LightCycler 2.0 instrument. The results showed that internalization was possible using contaminated seed, soil, and irrigation water in wheat seedlings, with internalization rates of 2, 5, and 10%, respectively. Even though the rates were low, to our knowledge this is the first study to demonstrate the ability of this strain to reach the phylloplane in wheat. In the head contamination experiment, all samples tested positive, showing the ability of E. coli O157:H7 to survive on the wheat head.

Soil versus Pond Ash Surfacing of Feedlot Pens: Occurrence of Escherichia coli O157:H7 in Cattle and Persistence in Manure†

2010 ◽  
Vol 73 (7) ◽  
pp. 1269-1277 ◽  
Author(s):  
ELAINE D. BERRY ◽  
JAMES E. WELLS ◽  
TERRANCE M. ARTHUR ◽  
BRYAN L. WOODBURY ◽  
JOHN A. NIENABER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sampling Period ◽  
Escherichia Coli O157 ◽  
Surface Material ◽  
Beef Heifers ◽  
Pond Ash ◽  
E Coli ◽  
Cattle Feces ◽  
Naturally Occurring ◽  
Survival Differences

Reducing Escherichia coli O157:H7 in cattle and their manure is critical for reducing the risk for human foodborne and waterborne illness. The objective of this study was to evaluate the effects of soil and pond ash surfaces for feedlot pens on the prevalence, levels, and/or persistence of naturally occurring E. coli O157:H7 and total E. coli in cattle (feces and hides) and manure. Cattle (128 beef heifers) were sorted among 16 pens: 8 surfaced with soil and 8 surfaced with pond ash. The prevalence of E. coli O157:H7 in feces decreased (P < 0.0001) during the study from 57.0% on day 0 to 3.9% on day 84 but did not differ (P ≥ 0.05) between cattle on soil and on pond ash pens at any sampling period. The prevalence of the pathogen on hides and in feedlot surface material (FSM) also decreased (P < 0.0001), with no effect of soil or pond ash surface (P ≥ 0.05). Similarly, levels of E. coli in FSM did not differ (P ≥ 0.05) at any sampling period, and there were no clear trends for survival differences of E. coli O157:H7 or E. coli in FSM between pond ash and soil surfaces, although E. coli populations survived at 5.0 log CFU/g of FSM on the pen surfaces 6 weeks after the cattle were removed. These results indicate that housing cattle on pens surfaced with pond ash versus pens surfaced with soil does not affect E. coli O157:H7 in cattle or their manure.

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